Experience with a new percutaneous port system, Percuseal, for intravenous injection in patients with haemophilia, von Willebrand disease and severe alpha1-antitrypsin deficiency

Measuring therapeutic relationship in the care of patients with haemophilia: A scoping review

OBJECTIVE

We conducted a scoping review of the tools used to measure therapeutic relationship in patients with haemophilia.

BACKGROUND

Haemophilia is an inherited bleeding disorder caused by a deficiency of a clotting factor in the blood. Therapeutic relationship is foundational to the management of patients with chronic diseases like haemophilia. A reliable and valid measurement tool for assessing therapeutic relationship is needed to evaluate the quality of care received by these patients, and to rigorously study the association between therapeutic relationship and the outcomes of treatment.

METHODS

We adopted the Arksey and O'Malley framework for scoping studies. The following electronic databases were searched for studies that measured a construct related to therapeutic relationships in haemophilia care: MEDLINE, EMBASE, CINAHL, PsycINFO and Scopus. We inventoried these studies, identified the measurement tools used, and described each tool by purpose, content, measurement properties and target population. We identified gaps in the current evidence and directions for future research.

RESULTS

There were 253 unique records retrieved in the search, and twenty studies were deemed relevant. Ten measurement tools were identified. None of the tools measured therapeutic relationship as a single entity; however, six tools measured constructs considered part of patient-provider relationship (eg trust, communication, working alliance). There has been little validation testing of these tools in haemophilia patient populations.

CONCLUSIONS

There is a need for a validated tool for measuring therapeutic relationship in the care of patients with haemophilia. This review provides a foundation for future research in this area.

Integration between a percutaneous implant and the porcine small bowel

Inflammatory bowel diseases, cancer or trauma may require removal of all or part of the intestines, leaving the patient with a need to wear external stoma appliances for collection of bowel contents. By connecting the small bowel to a percutaneous port, equipped with a sealing lid, a fully continent and leak proof stoma can be created without a need for permanently wearing stoma appliance. The prerequisites for a connection between a permanent, transabdominal implant and a visceral organ are largely unexplored. Stoma ports made of titanium were implanted in the abdominal wall of domestic pigs and a branch of distal ileum was inserted through the ports. After being followed for 1-3 weeks, the ports were removed and subjected to histological evaluation to study the influence of their shape, structure, and position on the tissue response. Particular focus was attended to the attachment of the ileal serosal surface to the implants inner structure consisting of a titanium mesh. Macroscopic examination revealed fistulas and formation of abscesses in 4 of 11 the retrieved implants. Histological examination revealed regenerated and well-vascularized collagenous tissue around the mesh structure inside the implant. The integration was complete or partial for 10 of 11 ports. Despite various degrees of inflammation and tissue ingrowth, it was demonstrated for the first time that the serosal surface of ileum was firmly attached to the internal structure of the implant. These experiments provide a basis for optimization of the implant and surgical procedure before long-term functional animal experiments.

Overview of the use of implantable venous access devices in the management of children with inherited bleeding disorders

Frequent infusion of factor concentrates may be challenging in young boys with haemophilia, especially if their disease is complicated by inhibitors. A central venous access device (CVAD) is often placed in young patients in need of repeated infusions for prophylaxis or immune tolerance induction. Although user friendly and capable of providing reliable venous access, these devices are associated with a high complication rate over time. In the haemophilia population, major complications include CVAD-associated infections and deep venous thrombosis, which is most often silent. Established risk factors for catheter-related infection include age less than 6 years at the time of CVAD placement and use of an external CVAD when compared with a totally implantable device such as a port. Avoidance of CVAD-related infections is facilitated by strict adherence to aseptic technique. The risk of deep venous thrombosis appears related to the duration for which the catheter is in place, with the risk increasing beyond 4 years. The promotion of a strict clinic policy in which CVADs are left in place for as short a time as possible should decrease the risk of complications. In rare cases where a totally implantable CVAD cannot be placed for technical reasons, an arteriovenous fistula may provide reliable venous access. In all cases, however, venous access via peripheral veins is preferred over CVADs.

Candida vertebra osteomyelitis in a girl with factor X deficiency

Candidal vertebra osteomyelitis is a rare condition which occurs primarily in immunocompromised patients. We report a 14-year-old girl with factor X deficiency who developed candida vertebra osteomyelitis during home therapy. The microorganism was probably from a contaminated peripheral cannula used for infusion of factor concentrate. This is the first such case in bleeding disorders to our knowledge.

Pharmacokinetics, thrombogenicity and safety of a double viral inactivated factor IX concentrate compared with a prothrombin complex concentrate

Therapeutic options for developing countries have to assure an optimum safety and efficacy and low-cost antihaemophilic concentrates. A single blind randomized crossover study was carried out in 12 previously treated HB patients, comparing the pharmacokinetics (PK), thrombogenicity (TG) and safety of two plasma-derived double-inactivated (solvent/detergent heating at 100 degrees C, 30 min) factor IX (FIX) concentrates, UMAN COMPLEX DI (product A) [plasma-derived prothrombin concentrates (PCC)] and a high purity FIX concentrate AIMAFIX DI (product B, HPFIX). In a non-bleeding state, they received one single intravenous dose 50 IU FIX kg(-1) of PCC or HPFIX, and after a wash-out period of 14 days, the other product. We evaluated acute tolerance and determined PK parameters based on FIX levels measured over a 50 h postinfusion period. We studied fibrinogen, platelets, antithrombin, F1 + 2, TAT, D-dimer, over a 360 min postinfusion period. Ten cases remained in on-demand treatment for 6 months, five with PCC and five with HPFIX. PK and anti-FIX inhibitors were repeated at 3 and 6 months. No inhibitors were detected. PK values (PCC vs. HPFIX): clearence (CL; mL h(-1) kg(-1)) 5.2 +/- 1.4 vs. 6.5 +/- 1.4; the volume of distribution at steady state (mL kg(-1)) 154.9 +/- 54.9 vs. 197.5 +/- 72.5; mean residence time (h) 29.7 +/- 8.1 vs. 30.7 +/- 9.2; T(1/2) (h) 22.3 +/- 7 vs. 23.5 +/- 12.3; incremental recovery (IR; U dL(-1) U(-1) kg(-1)) 0.96 +/- 0.17 vs. 0.76 +/- 0.13. HPFIX showed significant lower IR and higher CL. There were no differences in PK at 3 and 6 months. In TG, significant increments in TAT and F1 + 2 at 30 min and 6 h were found with PCC. Product B PK results agrees with reported results for other HPFIX preparations. Use of PCC product A has to consider its thrombogenic activity.

Use of pharmacokinetics in the coagulation factor treatment of patients with haemophilia

Dosing decisions for replacement coagulation factors in patients with haemophilia should be made on an individual patient basis, with the required dose dependent on factors including the clinical situation, the severity of the factor deficiency, and the location and extent of bleeding. Moreover, there is considerable variability in the pharmacokinetics of coagulation products that needs to be considered; in particular, with both factor (F) IX and FVIII products, there is considerable inter-patient variability in in vivo recovery and terminal half-life values. In the present report, we provide a practical guide to calculating and applying pharmacokinetic parameters relevant to the optimal dosing of coagulation products. We discuss the conduct of a pharmacokinetic study in an individual patient, how to calculate pharmacokinetic values from raw data and clinical situations where an individual pharmacokinetic study is helpful. We highlight the importance of considering an individual pharmacokinetic study in all patients starting a new coagulation product.

Tailored pharmacokinetic dosing allows self-administration and reduces the cost of IV augmentation therapy with human alpha(1)-antitrypsin

OBJECTIVE

Severe alpha(1)-Antitrypsin (AAT) deficiency (PiZZ) predisposes to the development of emphysema. Intravenous augmentation therapy with purified human AAT has been available since 1988. The dosage has varied from 60 mg/kg body weight once weekly to 250 mg/kg once monthly. We have found the dosage of 120 mg/kg every 2 weeks to be the most convenient for the patients. The treatment is very expensive. The objective of this investigation was to study whether tailored pharmacokinetic dosing of human AAT allows self-administration and reduces the total annual dose and cost of intravenous augmentation therapy.

METHODS

Five PiZZ individuals receiving purified human AAT at a dose of 120 mg/kg every 2 weeks were included in the study. Three patients had a percutaneous and one patient had a subcutaneous intravenous injection port system. After a 4-week interruption of the treatment an ordinary dose of 120 mg/kg human AAT was infused. Plasma AAT levels were determined preinfusion, postinfusion, and once daily for 10-14 days. The pharmacokinetic parameters of exogenous AAT were calculated for each patient. Based on these, individual dosage schemes were designed by computer simulation. The patients were treated with the new dose twice weekly for 4 weeks, and plasma AAT was determined immediately before the last two infusions.

RESULTS

At a dose of 1 or 2 g twice weekly the median annual consumption of human AAT was reduced from 286 to 156 g/patient. The trough plasma AAT level was maintained above 0.70 g/l, which is considered as protective. The three patients who had an implanted percutaneous venous port system learned to administer the treatment by themselves at home. The other two patients were treated at home by the district nurse.

CONCLUSIONS

The results of our study indicate that tailored pharmacokinetic dosing of human AAT reduces the total annual dose and cost of IV augmentation therapy. In addition, this dosing facilitates self-administration of AAT and allows treatment at home.